The address "lucb-ml@OPUS" is not an Internet style domain name. The
exploder ietf@CS.McGILL.CA has this address on its sublist, and
CSA.McGILL.CA does not recognize this host. (This error should have
gone to the sublist owner at CS.MCGILL.CA).

Usually a "host unknown" report is not acted on unless it is repeated
over a period of several days. In many cases the hosts really do
exist, but they're just down for a couple of days, or there are
network problems reaching it (or it's name serrver).

Most "User Unknown" error messages listed individually on the main
list get deleted. Those on a sublist, require a message to the
postmaster or list maintainer. They are asked to delete the
invalid user mailbox from their local list.

This is a case where the recipient was checking to see if his mailbox
was already on the list and if not to readd him. He was readded to
the list. A "user unknown" error message was received on the
confirming message that was sent notifying recipient that he had been
added.

I readded your name to the IETF list but there seems to be problems
with connections to DECnet hosts right now. I have seen lots of
errors like this lately. Postmaster, please check into this. JANUS
is not the only host with an error, there are other hosts like this
in trouble.

...means that the person on ERLANG:: has forwarded their mail to a
system that ERLANG does not know about. Decnet mail is not store-and-
forward, so decwrl (as smtp-to-decnet gateway) sees the end-system
error. Trying to be helpful, it sends it back to you.

My advice is to delete any addresses you have trouble with, if they are
in the .enet.dec.com subdomain.

If the Postmaster is "unknown" please delete him from your exploder
list "ietf@osi3.ncsl.nist.gov". I have been receiving error messages
like this one for several days now. If I don't hear from you, I will
have to delete the above mailbox.

I think I have found out what is wrong. For some reason (we can
discuss this below) your exploder is sending IETF mail to our
exploder (ietf@osi3.ncsl.nist.gov) through the machine
osi.ncsl.nist.gov. Now due to a recent subnet reconfiguration and
subsequent lack of update to our DNS servers, the DNS was returning
an incorrect address for osi3. Thus IETF mail would be sent to OSI,
which would try to forward it to OSI3 (using the wrong address).
OSI would think that OSI3 was down and dump the message, trying to
send a notice to Postmaster. OSI doesn't have an aliase for
Postmaster and thus the second error message that you saw.

Westine & Postel [Page 30]

RFC 1211 Problems with Mailing Lists March 1991
These two problems have been fixed on OSI. Now the question is what
address you have in your distribution list that would cause this
mail to go through OSI in the first place. I guess you might have
something like "ietf%osi3@osi.ncsl.nist.gov." The other interesting
point about your list is that we receive IETF mail to our exploder
directly from venera.

Thus I suspect that there are two entries for OSI3 on your
distribution list. One that gets relayed through OSI and one that
points directly to OSI3. If this is the case please deleted
everything except the "ietf@osi3.ncsl.nist.gov." address.

Your message has been received by the University of Toronto Computing
Services Postal System. A copy of it has been returned to you because
of difficulties encountered while attempting to deliver your mail.

Would you mind checking into this error message before I delete this
person from our list. I think it may be an internal forwarding
problem at MIT. If not let me know if there is a new address or if I
should delete this one.

I remember your request, and I also remember telling you that you are
not on our list (at least individually). There is an exploder
"netadm@MATH.UFL.EDU" maintained at UFL.EDU. You need to check with
the postmaster to see if you are on their list. If this is not the
case, here are the only other addresses I have from UFL.EDU

Many, many thanks for the reply: I did not, somehow, see your
previous reply -- perhaps you forwarded it to someone at UFL.EDU
instead of MATH.UFL.EDU? Or I missed it in the flow of mail I am
trying to abate.
No matter.

At any rate "netadm@math.ufl.edu" is indeed a local exploder, aliased
at the moment to myself and one of my assistants. It is local to the
"math.ufl.edu" subdomain, and not to "ufl.edu" as your records
indicate. I am the postmaster of the "math.ufl.edu", and you should
be able to verify "math.ufl.edu" has an MX record pointing to
"mathlab.math.ufl.edu". I am therefore mailing to you as root from
that machine.

Please remove "netadm@math.ufl.edu" from your list. I have quite
enjoyed the discussions, but the volume been overwhelming.

I will readd you to the IETF list. However, if I receive more error
messages like this, then I must take your name off the list again.
I've sent messages to the postmaster at DEC but the problem isn't
corrected. Your address isn't the only one, there's CALLON and a few
others.

Westine & Postel [Page 49]

RFC 1211 Problems with Mailing Lists March 1991
Maybe you can check into this. Here's the header from one of the
many error messages I received.

The error message that you sent is unfortunately my mistake and has
nothing to do with DECWRL. One day I reset protection on all my files
and directories and didn't realize that even the system did not have
the privilege to write mail messages on my disk. I discovered it only
after several people sent phone messages to me. Thanks for adding my
name again. I will try to be careful. -Raj